Messages in this thread | | | Subject | Re: [PATCH v5 11/13] KVM: s390: implement mediated device open callback | From | Pierre Morel <> | Date | Tue, 5 Jun 2018 14:19:53 +0200 |
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On 30/05/2018 16:33, Tony Krowiak wrote: > On 05/24/2018 05:08 AM, Pierre Morel wrote: >> On 23/05/2018 16:45, Tony Krowiak wrote: >>> On 05/16/2018 04:03 AM, Pierre Morel wrote: >>>> On 07/05/2018 17:11, Tony Krowiak wrote: >>>>> Implements the open callback on the mediated matrix device. >>>>> The function registers a group notifier to receive notification >>>>> of the VFIO_GROUP_NOTIFY_SET_KVM event. When notified, >>>>> the vfio_ap device driver will get access to the guest's >>>>> kvm structure. With access to this structure the driver will: >>>>> >>>>> 1. Ensure that only one mediated device is opened for the guest >> >> You should explain why. >> >>>>> >>>>> 2. Configure access to the AP devices for the guest. >>>>> >> ...snip... >>>>> +void kvm_ap_refcount_inc(struct kvm *kvm) >>>>> +{ >>>>> + atomic_inc(&kvm->arch.crypto.aprefs); >>>>> +} >>>>> +EXPORT_SYMBOL(kvm_ap_refcount_inc); >>>>> + >>>>> +void kvm_ap_refcount_dec(struct kvm *kvm) >>>>> +{ >>>>> + atomic_dec(&kvm->arch.crypto.aprefs); >>>>> +} >>>>> +EXPORT_SYMBOL(kvm_ap_refcount_dec); >>>> >>>> Why are these functions inside kvm-ap ? >>>> Will anyone use this outer of vfio-ap ? >>> >>> As I've stated before, I made the choice to contain all interfaces that >>> access KVM in kvm-ap because I don't think it is appropriate for the >>> device >>> driver to have to have "knowledge" of the inner workings of KVM. Why >>> does >>> it matter whether any entity outside of the vfio_ap device driver calls >>> these functions? I could ask a similar question if the interfaces were >>> contained in vfio-ap; what if another device driver needs access to >>> these >>> interfaces? >> >> This is very driver specific and only used during initialization. >> It is not a common property of the cryptographic interface. >> >> I really think you should handle this inside the driver. > > We are going to have to agree to disagree on this one. Is it not possible > that future drivers - e.g., when full virtualization is implemented - > will > require access to KVM?
I do not think that an access to KVM is required for full virtualization.
-- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany
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